"Storing the DNA of thousands of innocent young people as young as ten is unlikely to solve our crime problems, but is a costly way of stigmatising young people. If you're innocent, you shouldn't have your data on who you are kept for years."

A total of 1,087,474 profiles of children aged between ten and 17 have been loaded on to the DNA database since 2000 - the equivalent of 312 a day.

Of those, 412,670 - or 37 per cent - were aged between ten and 14, according to figures from the National Policing Improvement Agency.

The NPIA was unable to say how many of those are innocent but on average one in six people on the database are not convicted of a crime.

The Home Office published proposals for a review of the database in May, in the wake of a landmark European Court ruling that said a blanket policy of retaining profiles of innocent people indefinitely was illegal.

But under the plans, the DNA profiles of innocent people will remain on the national database for up to 12 years while some innocent children will also have their profiles kept for a similar period, although the majority will have them deleted within six years.

The proposals will mean that adults arrested, but not convicted, of terrorism or serious sexual or violent offences will have their profiles held for 12 years before they are deleted. The same applies for those under 18.

There are an estimated 5.3million profiles on the DNA database - accounting for about one in 10 people.

The database has doubled in size since 2002 but the number of crimes solved directly because of a DNA match has fallen over the period from 21,098 in 2002/03 to 17,614 last year.

Helen Wallace, director of Genewatch UK, a campaign group, said: "An excessive number of children and young people are being added to the database and there is no evidence that it is helping to solve serious crimes.

"The numbers should be significantly reduced and innocent people should be removed."